Hi... If you are talking about the actual Gallery having Description or Title text, it is not currently possible via the UI.. and... there is a bug. Not sure if its just Mac or Windows too, where you cannot even do it via the XML... It was once possible but something has occurred to make it buggy so now it does not work... Perhaps Beta 5 will have the fix....

I am sure it was Beta 2 that worked via the XML. It has never worked via the UI....

Also, I am not happy with the way the image widow opens to at full size either... It never used to do that.. The Gallery is one of those features that took a while to arrive and now its going backwards....